Why was ES2015 removed from tsconfig.json compilerOptions.lib?

[DakotaWray2]

What type of issue is this?

Question

What SharePoint development model, framework, SDK or API is this about?

💥 SharePoint Framework

Target SharePoint environment

SharePoint Online

What browser(s) / client(s) have you tested

• 💥 Internet Explorer
• 💥 Microsoft Edge
• 💥 Google Chrome
• 💥 FireFox
• 💥 Safari
• mobile (iOS/iPadOS)
• mobile (Android)
• not applicable
• other (enter in the "Additional environment details" area below)

Additional environment details

• browser version Chrome/Edge
• SPFx version 1.21.1
• Node.js version 22.x

Issue description

Curious as to why es2015 was removed from tsconfig.json compilerOptions.lib in 1.21.x? I use Fluent v9 by default for projects and without adding it back I'm unable to get TypeScript to play nice. Are there any adverse side affects from doing this in SPFx considering it's so opinionated? Thanks

[Amey-MSFT]

Hello @DakotaWray2,
Thank you for bringing this issue to our attention. We will look into it and get back to you shortly.

[Amey-MSFT]

Hello @DakotaWray2,
Apologies for the delay but have tried adding "es2015" to your tsconfig.json like so:
"lib": ["es2015", "es2016", "dom"]
Let me know if this helps or any further assistance in required.
Thanks!!

[DakotaWray2]

@Amey-MSFT Yes I have added it back. My question is why was es2015 removed. I do not see anything related to the change in the SPFx change log.
Thank you

[Amey-MSFT]

Hello @DakotaWray2,

You're right, since this isn't documented.
We will connect with the Engineering Team regarding this and let you know the updates as soon as we get one.

Thanks!!